Air-heating furnace



F. A. C. SKINNER.

AIR HEATING FURNACE.

APPLICATION FILED JAN. 15, 1920.

Patented June 15, 1920.

2 SHEETSSHEET I.

F. A. C. SKINNER.

AIR HEATING FURNACE.

APPLICATION FlLED JAN. 15. 1920.

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rnnn a. c. snmivna, or sr. LOUIS, MISSOURI.

AIR-HEATING FURNACE.

Specification of Letters Patent.

Patented June 15,1920.

Application filed January 15, 1920. Serial No. 351,544.

To all whom it may concern:

Be it known that T, Fnnn A. C. SKINNER, a citizen of the United States, residing at St. Louis, State of Missouri, have invented certain new and useful Improvements in Air-Heating Furnaces, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part hereof.

The present invention is directed to improvements in air heating furnaces, and has for its object the combination of a furnace which shall insure perfect combustion for its fuel, suitable provision being made to exercise automatic control of any smoke or unconsumed products of combustion whenever fresh fuel is being charged into the firebox. A. further object is to provide means for passing air through the bed of fuel in the,

fire box whenever the natural draft through the fire box is insufiicient to bring about the desired intensity of combustion for the elimination of the smoke. A further object is to construct a furnace which will present a maximum heating surface to the air currents traversing the outer casing of the furnace and at the same time cause the body of air to take up or absorb the greatest number of heat units from the heating surfaces before the same is discharged from the easing. The advantages of the invention will be fully apparent from the following detailed description in connection with the accompanying drawings in which- Figure 1 represents a side elevation of the furnace with parts shown in middle vertical longitudinal section; Fig. 2 is a vertical transverse section on the line 2-2 of Fig. 1; Fig. 3 is a horizontal section on the line 33 of Fig. 5; Fig. 4: is a front elevation of a portion of the furnace with outer casing removed, showing the fuel-charging door and mechanism controlling the air doors; Fig. 5 is a side elevation of Fig. 4 showing in addition a small section of the wall of the outer casing; Fig. 6 is a rear edge view of the cam for actuating the air-door; and Fig. 7is a development v1ew of the cam.

Referring to the drawings, 1 represents a conventional form of coal burning furnace provided a fuel-feed charging mouth 2 closedby'a horizontally swinging door 3, a grate 4 and an ash compartment 5 with the usual door 6 as well understood in the art." In the present embodiment of my inproducts leads from the center of the top of the furnace. The stove proper is preferably made in sections as shown (Fig. 1) for purposes of hauling and shipping, the end of one section being received by a recess or offset formed in the contiguous end of an adjacent section as fully indicated in Fig. 1, whereby an air tight joint is formed between the sections. The furnace is surrounded by an outer casing or jacket 8 which is formed atthe bottom in the rear of the furnace with an extension 8 for the housing of a suitable circulating fan or blower F, the same bein driven from a pulley 9 mounted on the shaft thereof, by a belt 10 leading from a pulley 11 on the shaft of a preferably electric motor M mounted on top of the rear casing extension 8. The top of the casing 8 has leading therefrom a series of air-distributing pipes 12 clustered about and in a measure anchored to the central flue 7 the connections between the air pipes and flue being made so as to provide an air-tight joint with the flue and prevent escape of the hot air from the casing except by way of the pipes. The outer walls of the furnace are provided with a series of spines or teats 13 disposed radially from the body of the furnace and extending partially across the hot air' chamber 0 between the furnace and outer casing 8, the spines being preferably cone-shaped and tapering outwardly as shown. The spines not only radiate heat but impart a rotary or turning motion to the air particles impinging against them,

this motion tending to thoroughly churn the air and bring a maximum amount of air particles into contact with the heat radiating surfaces of the spines, thereby thoroughly heating the air before the same is distributed for consumption by the pipes 12. The mouth 2 necessarily extends across the hot air chamber C through the wall of the outer casing 8 to permit the introduction of'the fuel into the fire pot of the furnace.

The rear wall of the ash compartment 5 is provided with an air opening 0 controlled by a sliding damper li operating in grooves or ways formed by the guide strips 15, 15, one end of the damper being coupled to a rod 16 operating loosely in the outer casing wall, and terminating outside the casing in a ring or finger-hold 17 for purposes of manipulation. Disposed on each side of the mouth 2 is an air inlet frame or mouth 18 having a front oblong opening normally closed by a vertically swinging door 19 sus pended by ears 20 from a hinge pin 21 carried by the lugs 22 leading from the top of the mouth 18, the front wall of the door being formed adjacent the hinge axis thereof with a centrally disposed lug 23 provided with an elongated inclined slot 8. Disposed transversely across the top of the mouth 2 are posts 24: between which is mounted a rock-shaft 25, the ends of the shaft terminating opposite the lugs 23 on the air inlet doors 19. Each end of the rock-shaft carries an arm 26 the free end of which terminates in a finger or bent portion h operating in the slot .9. It is obvious that with a rocking of the shaft 25 in proper direction the arms 26 will be swung outwardly, the fingers h thereof traversing the inclined slots 8 of the lugs 23 and pulling or swinging the doors 19 to open position (dotted position Fig. 5). The rocking of the shaft 25 in proper direction to open the doors 19 is accomplished by the opening of the fuel-charging door 3 through the following mechanism: Cast with or secured to one of the upper corners of the door and operating through an opening formed in the outer casing wall for its accommodation (Fig. 3) is a cam-track plate 27 provided with a camtrack 03 inclined to the horizontal as clearly shown in the development Fig. 7 and rear edge view Fig. 6, said cam-track being traversed by the free end of a curved arm 28 setscrewed to and adjustable along the 'rockshaft 25. The arm 28 likewise operates through an opening in the outer casing wall as shown in'Fig. 3. The low or closed end of the cam-track d is presented to the free end of the arm 28 when the door 3 is closed. When the door is swung open however for feeding fuel to the furnace, the arm 28 traverses the cam-track from the low to the high end, this action serving to. lift the free end of the arm and rock the shaft 25 in proper direction to swing outwardly the door-actuating arms 26, in which outward movement the doors 19 are caused to swing open so as to admit air into the fire box of the furnace through the uncovered openings of the mouths or frames 18. With the closing of the fuel door 3, the reverse action takes place, the doors 19 being allowed to gravitate back to closed position.

It will be seen from the foregoing that whenever it is desirable to increase the draft through the coals on the grate,'the operator by uncovering the opening 0 in the rear wall of the ash compartment 5 (by sliding the damper 14 the proper degree) will cause air to be delivered or forced into said compartment by the fan F, the amount of air thus admitted being regulatedby adjusting the position of the damper. Again, when charging green or fresh fuel into the furnace through the mouth 2 by opening the memes door 3, it is well known that large quantities of smoke are usually given off especially in the case of soft coal. This smoke is in a large measure consumed by the hot air admitted and forced into the fire box from the chamber 0 by the fan F through the openings left uncovered by the doors 19 which, as previously seen, swing to open position under the action of the cam 27 whenever the fuel door 3 is opened. The advantage of placing the opening 0 in the rear wall of the ash compartment is because it is then in direct line with the fan delivery, causing the air to be directly forced into the compartment and under the charge of fuel resting on the grate. From the foregoing it is obvious that the furnace is an admirable smoke con sumer and hence a highly efiicient heater. I may of course change the details of construction without in any wise departing from the nature or scope of the invention, the main object of which is to make suitable provision for shunting ofi a portion of the hot air in the casing G and directing the same into the fire-box for purposes of both increasing the draft and consuming the smoke.

Having described my invention what I claim isl a 1. In an air heating furnace, an inner furnace, an outer casing spaced therefrom and forming an air-circulating chamber therewith, a fuel-charging door leading from the fire-box of the furnace and operating outside the walls of the casing aforesaid, damper-controlled air openings on the furnace walls inside the casing establishing communication between the air-circulating chamber andthe space above the fuel in the fire-box, intermediate connections between the fuel-charging door and dampers of the air openings operating through thewalls of the casing for uncovering the air openings with an opening movement of the door, and an air moving apparatus discharging into the air chamber whereby, with an uncovering of the openings aforesaid, air from the air circulating chamber is forced through said openingsinto the space above the fuel.

2. In an air-heating furnace, an inner furnace, an outer casing spaced therefrom and forming an air-circulating chamber therewith, a fuel-charging mouth leading from the furnace across the chamber to the walls of the casing, a hinged door on the outside of the casing for closing the opening of said mouth,'air openings in the furnace walls leading to the space above the fuel in the stove, doors or dampers for controlling said o enings, a rock-shaft mounted on the fuelcharging mouth inside the air chamber, an arm or finger projecting from said shaft, a cam plate on the outer door adjacent the hinge-axis of the door operating through an opening in the wall of the casing and engaging said finger to oscillate the same with a swinging of the door in either direction, and thereby rocking the shaft aforesaid, and intermediate connections between the shaft and dampers aforesaid for actuating the latter and covering and uncovering the air openings with the closing and opening movements of the outer door respectively.

3. In an air heating furnace, an inner furnace, an outer casing spaced therefrom and forming an air-circulating chamber therewith, a fuel-charging mouth extending from the furnace across :the chamber through the walls of the casing, a hinged door outside the casing for closing said mouth, air openings in the furnace walls leading to the space above the fuel, hinged doors for covering said openings, a rock-shaft mounted across the top of the fuel charging mouth and extending to points opposite the airopenings aforesaid, arms rigidly coupled to 1 the rock-shaft and extending toward the air openings, said arms terminating in outwardly bent fingers, slotted lugs on the doors controlling the air openings for receiving said fingers, a cam-track plate carried by the outer dooriadjacent the hinge axis thereof and operating through an opening of the wall of the outer casing, and an arm leading from the rock-shaft through the casing wall and having its free end traversing the cam-track whereby the arm is oscillated vertically with a swinging of the outer door and the shaft rocked to cause the finger arms to open or close the doors of the air openings depending on whether the outer door is swung to open or closed position, the air from the air chamber bein free to pass into the space above the fue through the air openings when the latterare uncovered for a charging position of the outer door.

In testimony whereof I aifix my signature in presence of two witnesses.

FRED A. O. SKINNER.

Witnesses:

EMIL STAREK, N. E. BROCKMAN. 

